On board a crowded Red Line train near the Grand stop, Chantelle Sieren, of Cedar Rapids, Iowa, at center, rides toward Wrigley Field with her niece Olivia Gassman, 16, at left. The families were headed to see the Chicago Cubs play the Minnesota Twins. The Cubs won 10-6.
With 8 lines stopping at 145 stations, the Chicago Transit Authority's train system -- colloquially known as the "L" -- is an essential lifeline for the city. Annually, about 238,645,800 riders use the system.